Vahagn Vardanyan PhD Student

Vacuum Tight Metal to Ceramic Joining

CANDLE SRI, Yerevan, Armenia, 12/03/2015

Thesis Supervisor – Vardan Avagyan

Ceramic Properties

In general, most ceramic are:

• Hard, • Wear-resistance, • Brittle, • Refractory, • Thermal insulators, • Electrical insulators, • Nonmagnetic, • Oxidation Resistant, • Prone to thermal shock, • Chemically stable.

Advanced Ceramics Materials

• Aerospace, • Nuclear Waste Containment, • Military Armor Systems, • Automotive /Engine, • Semiconductors, • Heat Exchangers, • Fluid Handling, • Medical, • Metallurgy,

Aerospace Silicon Nitride

Silicon Nitride provide Superior

mechanical reliability wear resistance.

• Jet engine igniters. • Missile radomes. • Aircraft engine parts. • Hydraulic wear components.

Ceramic Cutting Tools (Si3N4, etc.) Semiconductor Applications

- Vacuum Chucks – AlN, - RF Windows – Y2O3, - Focus Rings,

- Gas Distribution Plantes – Si3N4, - Crucibles – SiO2, - Heaters – AlN.

Silicon Nitride

• Extreme Thermal Shock Resistance, • High Toughness (for ceramic), • Strong electrical insulator, • 1/3 weight of steel, • RF transparent.

Boron Carbide

Nuclear Waste Containment

Neutron absorption and shielding of nuclear

fuel storage and transport

Bayard Alpert Gauge Molecular Pumps

Metal to ceramic junctions in UHV technology

UHV multiple pin feedthoughs

Vacuum Chambers for Accelerators

Metal – Ceramic Joint Parameters

- High Mechanical strength,

- Outgassing Low Level,

- Reliable during long time,

- Electro – Magnetic Parameters, - Low Material Penetration,

- Dimensional Stability,

- Thermal shock resistance.

Parameters

Interferometric profilometer

Diffusion Welding Laboratory

- Pressure,

- Temperature,

- Time,

- Environment

Diffusion Welding , Brazing parameters

Tunnel Furnace

Induction-Vacuum Furnace

Vacuum Furnace

Regime of Metalization (Our experiments)

Phase Diagram Mn-Mo

Phase Diagram MnO - Al2O3 Phase Diagram TiO - Al2O3

Materials Melting Point

(°C)

Density

(g·cm− )

Thermal Expansion

µm·m− ·K− (at 25 °C)

Description Brinell Hardness

(MPa)

1 Mo 2623 10.28 4.8 paramagnetic 1370–2500

2 Mn 1246 7.21 21.7 paramagnetic 196

3 Ni 1455 8.908 13.4 Ferromagnetic 667–1600

4 Cu 1084.62 8.96 16.5 diamagnetic 235–878

5 Ti 1668 4.506 8.6 paramagnetic 716–2770

6 Ag 961.78 10.49 18.9 diamagnetic 206-250

7 Kovar 1450 5.5

Material Descriptions

Curry point for different materials

Coefficient of

Thermal expansion

Cutting, grinding, etc.

Our Experiments

Methods of metallization layers

Coating type Temperature 0C

duration Cooling speed 0C/min

Environment

Mn, Mo (22X, 22XC, A-

995, M-7)

1 270 – 1 400 20 - 40 5 - 10 N2 : H2 = 2 : 1 N2 : H2 = 3 : 1

dew point

+15 - +250C

Mo, Mn, Si 1 280 – 1 320 40 Cooling - 4.2 N2 : H2 = 3 : 1 dew point

+15 - +250C

Regime of Metalization

Ceramic Cutting Machine

Our Experiments

Ceramic - Type Metallization Past Concentration %

Cearmaic Steatit, K-1 Mo : Fe 98 : 2

Ceramic Forsterit, ФС-5Л, Ф-555

Mo : Mn

Mo : TiH2 : Al2O3

96 : 4

63.8-74,0.8-6.1

Alumina silicate ceramic WC : TiC : Fe 60 : 10 : 30

Alumina

22X, 22XC

Mo

Mo : Mn

Mo : Mn : Si

Mo : Mn : TiH2

Mn : Mo2B5 , Mo

100

80 : 20

80:20 (+5)

80 :20 : 10

20 : 10-15 : 70-65

M7 Mo ; Mn : MoB

Mo : Mn : MoSi2 Mo ; Mn : C-48

62.5 : 20 : 17.5

77 : 20 : 3

75 : 20 :5

- 4 Mo : Mn : Si 75-78 : 20 : 5-3

A-995 Mo : Mn : Mo2B5 : Д-22 74 : 15 : 5 : 6

Sapphirite Mo : Mn : V2O5 75 : 20 : 5

Policore Mo : Mn : Si 80 : 20 : (+5)

Monocrystal sapphire Mo : Mn : Mo2B5 : 74 : 15 : 5 : 6

Rubine Mo : glass CT-1 70 : 30

Beryllium ceramic Mo : Mn : Si 80 : 20 : (+5%)

Thermal expansion of various oxide ceramic and metallic materials as a function of temperature.

Solder for Brazing

Wettability of Solder

Solder Surface Energy

Mechanical stress calculation of metal - ceramic junctions

- Review of methods,

- Design – calculation – simulation, - Experiment,

- Testing

Types of junction

Kovar

Mass Spectrometry

Residual gas analysis in high vacuum

Microstructuries

Type Purity

(mass - %)

Density

(g/cm3)

C 98,43 3.75

Al23 99,70 3.81

D1 99.70 3.84

D2 99.73 3.91

D3 99.74 3.90

U 99.74 3.93

AL24 99.77 3.59

Windows for Particle Accelerators

- Diamond windows,

- Silica windows,

- Sapphire windows,

- Kapton Windows,

- Titanium Windows,

- Beryllium Windows,

- Alumina Windows,

- Glass Windows

- …..

7056 Glass Viewport

Kovar sleeve Sapphire windows

Direct Brazing of Sapphire to Niobium

Niobium to Sapphire

Diffusion brazing methods of difficult geometry dissimilar details.

Patent number – AM201453 Vardan Shavarsh Avagyan, Vahagn Vanik Vardanyan

Intellectual Property Agency of the Republic of Armenia

New Diffusion Brazing Method

RF Windows

Main Requirements.

- High Mechanical strength,

- Outgassing Low Level,

- Reliable during long time,

- Thermal shock resistance,

- Necessary Electro – Magnetic Parameters, - Low Material Penetration,

- Necessary Thermal Conductivity,

- Dimensional stability.

1. waveguide, 2. coaxial

3. Waveguide - coaxial

RF Windows

1. Vacuum Tight parameters at 1011Pa and max. working temperature16000C,

2. low gas permeability 800 - 10000C – for 02, N2, Ar, etc., 3. Minimum dielectric loss, 109 – 1011 Gigahertz, 500- 7000C, 4. High Electrical strength (vacuum, inert gas, ),

5. High mechanical strength,

6. High thermal conductivity,

7. Multiple thermal shock,

8. Joining ability to metals,

9. Radiation durability,

10.High Purity.

Parameters of ceramic for RF Windows

Temperature range -60 to +6500C

Max pressure - 10kgf/cm2

Alumina Ceramic RF Windows

Types of RF Windows

d – толщина диэлектрика

Beryllium Windows

X-Ray Windows

loss of power

Diffusion Brazing and Welding for RF Windows

Types of RF Windows

Cerami

c Type

L·mm ·

mmHg

cm/cm2 ×103

Gas type %

H2 N2+CO CO2 H2O

22XC 1.2 55 40 3 2

22X 0.6 55 40 3 2

A-995 1.9 47 41 10 2

M-7 3.8 52 43 3 2

102 2.0 57 31 10 2

Ф-17 3.0 48 44 6 2

C-14 3.6 50 42 5 3

Parameters of RF Ceramic. Nitrid Bore

- Necessary RF parameters,

- Mechanical and thermal parameters

- High Mechanical strength,

- Outgassing Low Level,

- Reliable during long time,

- Thermal shock resistance,

- Electro – Magnetic Parameters, - Low Material Penetration,

- Corrosion resistance,

- Dimensional stability.

RF Windows

Various Ceramics for RF Window

WESGO A L300 COORS AD995 KYOCERA 476SS NTK UHA99

KEK

Metalize:

- Mo (85%) + Mn (10%) + Glass (3-7%) for 99.5% ceramic

- Mo (85%) + Mn (10%) + Ti + Glass (3-7%) for 99.9% ceramic

- Thickness: 15~20 µm

- Sintering Temperature: 1350 °C

Metallizing for High Purity Ceramic KEK

Glass 3% Glass 5% Glass 7%

For Brazing

Use activate type brazing material: Au + Cu + Ti (1~2%)

Temperature: ~900 °C in vacuum

KEK

UHV Vacuum Test Stend

Residual gas analysis in high vacuum

Outgassing

Etc.

Software

Thank You!